Multi-ethnic states built and held together by conquest under a single ruling authority styled emperor, khan, shah or an equivalent imperial title, spanning many peoples, languages and formerly independent polities under one administration. Belongs here: dynastic conquest states from the Old Babylonian Empire and the Achaemenid Empire through the Roman successor empires (Byzantine, Holy Roman), the Mongol Empire and its khanates, the Islamic and Asian gunpowder empires (Ottoman, Mughal, Qing), the nineteenth and twentieth century colonial and continental empires (British, Russian, German, Japanese) and twentieth century imperial dictatorships that styled and conducted themselves as a Reich or empire in ambition and practice. Does not belong here: a hereditary monarchy ruling one people or territory without an imperial title or a conquered multi-ethnic base, filed instead under Kingdoms and Principalities, and a present-day sovereign state, filed under Modern Monarchies or Modern Sovereign Republics regardless of an earlier imperial past.